# CVE-2025-58056: Netty is vulnerable to request smuggling due to incorrect parsing of chunk extensions

> CVE-2025-58056: Netty is vulnerable to request smuggling due to incorrect parsing of chunk extensions. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2025-58056
Last updated: 2026-10-19T17:10:00Z

- Published: 2025-09-03 20:56 UTC · Updated: 2026-10-19 17:10 UTC · Assigner: GitHub\_M
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS: 0.71%, 53th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-444

## Description

Netty is an asynchronous event-driven network application framework for development of maintainable high performance protocol servers and clients. In versions 4.1.124.Final, and 4.2.0.Alpha3 through 4.2.4.Final, Netty incorrectly accepts standalone newline characters (LF) as a chunk-size line terminator, regardless of a preceding carriage return (CR), instead of requiring CRLF per HTTP/1.1 standards. When combined with reverse proxies that parse LF differently (treating it as part of the chunk extension), attackers can craft requests that the proxy sees as one request but Netty processes as two, enabling request smuggling attacks. This is fixed in versions 4.1.125.Final and 4.2.5.Final.

## Affected vendors and products

- netty: netty

## Tracked companies

- [Jira](https://rewindex.com/company/jira.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-58056)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2025-58056)
- [https://datatracker.ietf.org/doc/html/rfc9112\#name-chunked-transfer-coding](https://datatracker.ietf.org/doc/html/rfc9112#name-chunked-transfer-coding)
- [https://github.com/JLLeitschuh/unCVEed/issues/1](https://github.com/JLLeitschuh/unCVEed/issues/1)
- [https://github.com/netty/netty/commit/edb55fd8e0a3bcbd85881e423464f585183d1284](https://github.com/netty/netty/commit/edb55fd8e0a3bcbd85881e423464f585183d1284)
- [https://github.com/netty/netty/issues/15522](https://github.com/netty/netty/issues/15522)
- [https://github.com/netty/netty/pull/15611](https://github.com/netty/netty/pull/15611)
- [https://github.com/netty/netty/security/advisories/GHSA-fghv-69vj-qj49](https://github.com/netty/netty/security/advisories/GHSA-fghv-69vj-qj49)
- [https://w4ke.info/2025/06/18/funky-chunks.html](https://w4ke.info/2025/06/18/funky-chunks.html)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2025-58056 · Markdown: https://rewindex.com/cve/CVE-2025-58056.md · JSON: https://rewindex.com/api/v1/cves/CVE-2025-58056 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:17:06.421Z